Weight gain and breast yield of large white male turkeys fed diets varying in protein content.

Large White male turkeys were reared in floor pens to 20 wk of age. Diet changes were made every 4 wk, with dietary energy levels kept similar for diets within a period, and changes made in protein levels. Although significant differences in weight were noted at 4 and 8 wk, these diminished with age such that at 20 wk no significant differences were noted. Feed intakes paralleled weight gains. A sample of birds was taken every 4 wk for a measurement of breast meat (excluding skin) and composition. Although changes in dietary protein levels did not affect weight gains to 20 wk of age, breast protein yields were significantly reduced by lowered dietary protein levels. Breast meat varied from 15% of live weight at 4 wk of age to 23% at 20 wk. Protein composition of breast meat varied between 90 and 95% (DM basis), and was estimated to be in excess of 50% of edible carcass protein. With such a high level of edible carcass protein coming from breast meat, it is suggested that yield of breast protein be used as a parameter in determining optimum protein and amino acid requirements of heavy weight turkeys.